About

Jon Miller studies compact objects such as black holes and neutron stars to understand their basic properties, how gas falls onto and is ejected from them, and their implications for general relativity. His group is using data from the Chandra X-ray observatory to explore black hole spin (see below) along with the winds and jets they produce. They’re interested in both the fate of the accreted gas and the reasons some black holes appear to eject vastly more material than others. They plan to use the forthcoming Astro-H X-ray observatory to more accurately measure the speed of these winds, how close to the black hole they occur, and how much material is carried away. His group is leading a large multi-wavelength survey with the Swift mission to detect new neutron stars, black holes, white dwarfs, and supernova remnants within the Milky Way.

Notable Results

Miller proposed using the width of X-ray spectral lines to measure the spin of stellar-mass black holes. This was the first technique that could assess spin independent of a black hole’s mass, distance, or orientation, and was useful for comparing spin across a broad mass scale. The technique has become widely adopted and is being used on the full set of stellar-mass black holes in our galaxy. Because the more spin a black hole has the more radiation it is capable of emitting, these measurements can help clarify how black holes contribute to the energy budget of the universe.